Problem: $ { \left[\begin{array}{rr}{3} & {-1} \\ {4} & {-2} \\ {1} & {2}\end{array}\right]+\left[\begin{array}{rr}{-2} & {3} \\ {-2} & {1} \\ {2} & {4}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{3}+{-2} & {-1}+{3} \\ {4}+{-2} & {-2}+{1} \\ {1}+{2} & {2}+{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{1} & {2} \\ {2} & {-1} \\ {3} & {6}\end{array}\right]}$